CVE-2026-64380 Details
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.
A vulnerability in the Linux kernel's SMB client has been addressed, specifically related to the parsing of POSIX Security Identifiers (SIDs). The issue arose because the function responsible for reading SIDs did not properly validate the length of the data, allowing for buffers with insufficient bytes to be processed. This could lead to the acceptance of truncated SIDs, potentially causing issues in client paths that rely on this parsing. The vulnerability has been fixed by ensuring that the function requires an adequate buffer length before reading the subauthority count from the SID, thereby preventing the acceptance of incomplete data.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. Instructions for downloading the patched version are available on the Linux kernel's official website.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da | kernel.org | Patch |
| https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b | kernel.org | Patch |
| https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61 | kernel.org | Patch |
| https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59 | kernel.org | Patch |
| https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4 | kernel.org | Patch |
| https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422 | kernel.org | Patch |
| https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980 | kernel.org | Patch |
| https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 5.7, < 5.10.261 >= 5.11, < 5.15.212 >= 5.16, < 6.1.178 >= 6.2, < 6.6.145 >= 6.7, < 6.12.96 >= 6.13, < 6.18.39 >= 6.19, < 7.1.4 7.2 rc1 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 8, 2026 | Initial Analysis | [email protected] |
| Aug 17, 2026 | CVE Modified | kernel.org |
| Jul 27, 2026 | CVE Modified | kernel.org |
| Jul 25, 2026 | New CVE Received | kernel.org |